package com.hansming.bss.common.utils;

import java.awt.image.BufferedImage;  
import java.io.File;  
import java.io.IOException;  
import java.math.BigDecimal;  
  
import javax.imageio.ImageIO;  
  
import net.coobird.thumbnailator.Thumbnails;  
  
import org.apache.commons.lang3.StringUtils;  


public class ImageCompress {
	
	 public static void main(String[] args) {  
		  
		 ImageCompress.commpressPicForScale("C:\\Users\\Dante\\Pictures\\Screenshots\\abcde.png",  
				 "/hansmingbss/userfiles/1/images/photo/2018/01/123123.jpg", 500, 0.8); // 图片小于500kb  
	    }  
	  
	    /** 
	     * 根据指定大小和指定精度压缩图片 
	     *  
	     * @param srcPath 
	     *            源图片地址 
	     * @param desPath 
	     *            目标图片地址 
	     * @param desFilesize 
	     *            指定图片大小，单位kb 
	     * @param accuracy 
	     *            精度，递归压缩的比率，建议小于0.9 
	     * @return 
	     */  
	    public static String commpressPicForScale(String srcPath, String desPath,  
	            long desFileSize, double accuracy) {  
	        if (StringUtils.isEmpty(srcPath) || StringUtils.isEmpty(srcPath)) {  
	            return null;  
	        }  
	        if (!new File(srcPath).exists()) {  
	            return null;  
	        }  
	        try {  
	            File srcFile = new File(srcPath);  
	            long srcFileSize = srcFile.length();  
	            System.out.println("源图片：" + srcPath + "，大小：" + srcFileSize / 1024  
	                    + "kb");  
	  
	            // 1、先转换成jpg  
	            Thumbnails.of(srcPath).scale(1f).toFile(desPath);  
	            // 递归压缩，直到目标文件大小小于desFileSize  
	            commpressPicCycle(desPath, desFileSize, accuracy);  
	  
	            File desFile = new File(desPath);  
	            System.out.println("目标图片：" + desPath + "，大小" + desFile.length()  
	                    / 1024 + "kb");  
	            System.out.println("图片压缩完成！");  
	        } catch (Exception e) {  
	            e.printStackTrace();  
	            return null;  
	        }  
	        return desPath;  
	    }  
	  
	    private static void commpressPicCycle(String desPath, long desFileSize,  
	            double accuracy) throws IOException {  
	        File srcFileJPG = new File(desPath);  
	        long srcFileSizeJPG = srcFileJPG.length();  
	        // 2、判断大小，如果小于500kb，不压缩；如果大于等于500kb，压缩  
	        if (srcFileSizeJPG <= desFileSize * 1024) {  
	            return;  
	        }  
	        // 计算宽高  
	        BufferedImage bim = ImageIO.read(srcFileJPG);  
	        int srcWdith = bim.getWidth();  
	        int srcHeigth = bim.getHeight();  
	        int desWidth = new BigDecimal(srcWdith).multiply(  
	                new BigDecimal(accuracy)).intValue();  
	        int desHeight = new BigDecimal(srcHeigth).multiply(  
	                new BigDecimal(accuracy)).intValue();  
	  
	        Thumbnails.of(desPath).size(desWidth, desHeight)  
	                .outputQuality(accuracy).toFile(desPath);  
	        commpressPicCycle(desPath, desFileSize, accuracy);  
	    }  
}
